Residence was not listed; 49 years old.
Enlisted on 8/10/1861 at Oneida, NY as a Captain.
On 9/4/1861 he was commissioned into "Oneida" Co. NY Indpt Cavalry
He was Mustered Out on 12/10/1864 at Rochester, NY
(Not commissioned Captian)
Sources used by Historical Data Systems, Inc.:
- New York: Report of the Adjutant-General

This company was organized at Oneida, and there mustered
in the service of the United States for three years, under the
command of Capt. Daniel P. Mann, September 4, 1861. It was
recruited mainly at Oneida, Salisbury, Stockbridge, Hamilton,
Otisco, Eaton, Nelson Flatts, Vienna and Chittenango. It left
the State in September, 1861, and served at the headquarters of
the Army of the Potomac, performing escort and guard duty, and
furnishing couriers, etc. At the expiration of its term of
service, those entitled thereto were discharged, and the
company retained in service until June 13, 1865, when,
commanded by Capt. James E. Jenkins, it was honorably
discharged and mustered out near Washington, D. C.

Source: Phisterer, p. 1,187

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April 25, 1863 - Your [Col. John P. Taylor, Cmd. Cavalry Picket, Cmd. King Geo. CH, 1st Pennslyvannia] letter of this date has been received and laid before the commanding general, who directs that you at once take measures to carry into effect your proposition to send a detachment down the. Neck for the purpose of capturing any small parties of the enemy that may be found in that quarter, of breaking up contraband trade, of seizing mails being conveyed to and from the enemy's lines, seizing any supplies intended for the enemy, and of making arrests of such citizens as shall appear to be actively engaged against us.

The general wishes your party to move rapidly, and accomplish as much as possible inside of four days. The movements should, when practicable, be made at night, so as to take the enemy by surprise. Great care and discretion should be exercised in making arrests. The party will find an abundance of forage on the Neck. All provisions and forage likely to be used by the enemy, and not needed by our own troops, will be destroyed.

Captain Mann, commanding company of Oneida cavalry, has been directed to report to you temporarily with a small party, and the general wishes you to employ him in co-operation with your own detachment. The general wishes to have Heathsville visited. [OR V25, Pt. 2, p. 249]

.....

April 25 - The major-general commanding approves of your [Col. Taylor] proposition to send an expedition down the Neck for the purpose of capturing any dismounted men that are on this side. Captain Mann, of the Oneida cavalry, with a small force, will be sent down in order to strengthen the detachments that you send down. It is desired that you should send two detachments, one to operate by the River road the other to move on a parallel line at the same time by the road running along the center of the Neck. In order to accomplish the purposes of seizing any parties there and capturing any mails at Warsaw, Farnam's, Leeds, Heathsville, or any of the towns on the route, it will be necessary that you should make rapid marches and take these places by surprise.

General Reynolds, of the First Corps, will send a small party of cavalry down on the Potomac side of the Neck, to move to-night, to seize a signal party supposed to be operating at that point, near Machodoc Creek.

You should be very careful in the arrests you make not to harass, annoy, or imprison innocent citizens. The command will find on the march plenty of forage for their horses. All means of transportation which have been used for conveying subsistence to the enemy should be destroyed. Any boats or barges you may find on the Rappahannock side you should so thoroughly destroy that they cannot be used. You should seize any mails that can be gotten hold of, stop the conscription, supply the commands, giving receipts, according to forms prescribed in orders, for any forage or supplies taken. Upon their return, they should all meet and come back together, in order to be in strength.

Captain Mann will be furnished with a copy of this letter, to report to you about dusk. Expeditions have been down the Neck before several times. If you should find wagons, and animals to draw them, you could bring away provisions and bacon in large quantities from parties likely to convey them to the enemy, giving proper receipts therefor.

The foregoing is the supplementary letter of instructions referred to in my communication of this morning. A copy has been furnished Captain Mann.
[OR V.25, Pt. 2, pp.249/50]

There are no follow up reports in the Official Records

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On this raid, Capt. Mann's detachment consisted of 2 officers and 35 men.